The future of plant disease detection

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For many years, plant breeders have been developing varieties with natural resistance to certain problematic diseases, and growers have employed many scouting techniques and preventive measures to avoid them. In the ornamentals market, a diseased plant is often destined for the compost pile, as an ugly, diseased plant won’t sell, and may mean failure in the garden for the consumer.

Research Scientist and Expert Systems Specialist Dr. David Gholami, who comes from the world of industrial automation, understands the added complexities that come along with selling a living product that is susceptible to disease. “[Industry and consumer] demand is more challenging [in the horticulture industry] than other industries,” Gholami says. “People have a more precise definition of what they want in a good product.” That means the plant must arrive disease-free and visually appealing to the market in order for a consumer to purchase it.

Gholami, along with his team at Vineland Research and Innovation Centre in Ontario, is working on a high-tech solution to help growers with disease detection in the greenhouse. In Gholami’s words, this project is “about detecting plant diseases before they visually manifest.” That’s to say, it’s centered around helping growers to address the problem before traditional disease scouting methods would have found the disease in a crop.
“We are targeting major diseases for vegetable greenhouses and some for floral greenhouses,” Gholami says. “We’re using hyper spectral systems and other sensory systems.” On a basic level, hyper spectral imaging is technology used to see wavelengths that are out of the normal range of vision of the human eye, Gholami says. There are three different sets of sensory systems being used in this project, according to Gholami, including the hyper spectral system and two others that are slightly more advanced.
“We are using these technologies to monitor the plants and ‘see’ the signs of stress at the very earliest stage before they visually manifest on the plant,” he says. And being able to “see” this information enables growers to learn more about plant stress. They can then analyze that information to understand the overall health of the plant and whether or not it’s diseased, and take the appropriate next steps.

Currently, greenhouse growers use many different environmental control systems to observe and maintain ideal conditions that will provide plants with a setting to promote optimal growth. However, disease problems can infiltrate the greenhouse even when these control systems are functioning well. This project is also examining how those other systems can be complementary to the disease detection technology they are working on. “We think about this system as complementary to our [smart] irrigation system,” Gholami says. “If you put them together, they become a stress detector [for the plants].”

Gholami says that we can relate this technology to a futuristic visit to a doctor’s office. At this doctor’s office, you would enter a high-tech machine that would analyze your body and determine whether or not you would develop a disease two months from now, even if you’re not showing any symptoms yet. “You’re talking about that kind of technology, but for plants,” he says. “So you can see the challenges that are involved.”

Vineland isn’t the only institution working on visually based disease detection technology, Gholami says. “All advanced research institutes around the world are working on this technology,” he says. Researchers in the Netherlands, U.S. and Canada are doing studies on it. “This will be one of the most state-of-the-art technologies if we can figure it out, but it’s quite complicated,” he says. Advancements in these areas could be a key to further streamlining the disease control process in a greenhouse, which is exciting news for growers.